POS0638 SURVIVAL OF BIOSIMILAR ANTI-TNFΑ BLOCKERS COMPARED TO ORIGINATOR MOLECULES IN RHEUMATOLOGY: RESULTS FROM THE BIOBADASER COHORT
Authors: M. P. Martínez-Vidal, C. Fernández-Carballido, L. Otero-Varela, F. J. Manero Ruiz, C. Rodríguez-Lozano, S. Manrique Arija, C. Campos Fernández, V. Jovani, L. Expósito, M. Colazo, J. García-González, F. Sánchez-Alonso, I. Castrejon
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Recent data from a large cohort showed that biosimilars had no shorter survival than their originator molecules [1]. Although the survival of biological therapies in real practice has been recently analyzed in Spanish patients with rheumatic diseases (2), we do not know if there are differences in treatment survival, depending on whether the patients receive an originator or a biosimilar molecule. <h3>Objectives</h3> The main objective of this study was to compare the retention rate between subcutaneous biosimilar TNFα-blocker molecules and their originators. The secondary objective was to analyze the factors associated to drug survival. <h3>Methods</h3> Retrospective analysis of BIOBADASER cohort, the Spanish multicenter prospective registry of patients with rheumatic diseases with biological disease-modifying anti-rheumatic (bDMARD) or targeted drugs. We included patients who received originator or biosimilar molecules of etanercept or adalimumab for at least 6 months until December 2020. To avoid the <i>nocebo</i> effect, patients who had switched from the innovative molecule to the same biosimilar molecule were excluded. The drug retention rate was calculated considering all reasons for discontinuation as completion events, and analyzed using Kaplan-Meier curves for first and subsequent lines of treatment, adjusting for the use of concomitant conventional synthetic DMARD (csDMARD) and corticosteroids (CS). Hazard ratios (HR) were estimated using a Cox regression model, to identify factors associated to differences in the survival rates of biosimilar compared to originator molecules. <h3>Results</h3> A total of 4566 courses of treatment (2543 of adalimumab and 2023 of etanercept) and 4106 patients were included for this analysis. Biosimilars were used as 1<sup>st</sup> treatment in 51.1% of patients, as 2<sup>nd</sup> line in 39.2% and 3<sup>rd</sup> or subsequent lines in 37.7%. The use of csDMARD occurred in 63.8% of the cases and CS in 37.3%. Demographic and basal clinical characteristics of the patients are shown in Table 1. The main reason for discontinuation was inefficacy or loss of efficacy (58.1%), followed by adverse events (18.8%), pregnancies (3.5%), and remission (3.3%). The survival was higher for biosimilars (HR 0.68, 95% CI 0.53-0.98; p=0.002). Neither the disease type, sex, age, disease duration nor the concomitant treatments with CS or csDMARD influenced the retention rate. The survival was lower in smokers (HR 1.23, CI1-1.52; p=0.046), patients with overweight (HR 1.3, 95% CI 1.1-1-6; p=0.006) and 3<sup>rd</sup> line of treatment (HR 1.34, 95% CI 1.1-1.7; p=0.014). Among patients with adalimumab, survival was associated with JIA (HR 0.37, CI 0.16-0.85; p=0.015) and AS (HR 0.63, CI 0.43-0.91; p=0.015). <h3>Conclusion</h3> In real world practice, the survival of biosimilar TNFα-blocker molecules adalimumab and etanercept is higher compared to their originator molecules. Smoking, overweight and drug use in 3<sup>rd</sup> or subsequent lines of treatment are associated with a lower retention rate. <h3>References</h3> [1]- Di Giuseppe D. Rheumatology (Oxford) 2022;6:3596. [2]- Prior-Español A. Sci Rep 2021;11:11091. <h3>Acknowledgements</h3> This study has been possible thanks to all the rheumatologists collecting data for the BIOBADASER registry. <h3>Disclosure of Interests</h3> None Declared.